Antibiotic/benzoyl peroxide dispenser

ABSTRACT

Two separate compositions, one containing an effective anti-acne treating amount of a first active ingredient and one containing a second active ingredient that is incompatible with the first active ingredient are packaged within and dispensed from a common dispenser. By packaging these two active ingredients in this manner, long shelflife and convenient dispensing and application are provided.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/121,839 filed Apr. 12, 2002 which is a continuation-in-part ofapplication Ser. No. 09/734,748 filed on Dec. 12, 2000, now U.S. Pat.No. 6,462,025. The entire disclosure of each of these applications arehereby incorporated by reference.

BACKGROUND

1. Technical Field

This disclosure relates to compositions and apparatus for dispensing twodistinct substances. More specifically, this disclosure relates tocompositions and apparatus which allow long-term storage and subsequentdispensing of two compositions, to wit, a first composition containing afirst active ingredient for treating acne and a second compositioncontaining a second active ingredient that is incompatible with thefirst active ingredient.

2. Background of Related Art

Acne is a common inflammatory disease of human skin, and concentrates inskin areas where sebaceous glands are largest, most numerous, and mostactive. In its milder types, it is a more or less superficial disorderwhich is evidenced by slight, spotty irritations and ordinary skinhygiene is a satisfactory treatment. However, in the more inflammatorytypes of acne, bacterial invasion of or about the pilosebaceousfollicles occurs and pustules, infected cysts and, in extreme cases,canalizing inflamed and infected sacs appear. These lesions may becomeextensive and leave permanent, disfiguring scars.

Acne is very common by puberty and at least 80% of teenagers areafflicted. The facial eruptions are known to cause such psychic traumain many adolescents that they find it difficult to make personaladjustments and consequently, withdraw and self-pity occur. The sufferermay be constantly aware of the obvious facial blemishes. For thesereasons a medicinal preparation and treatment are of definite benefitand may eliminate the need for psychotherapy.

To reduce the severity of acne, various forms of medication havepreviously been topically applied to the skin. Antibacterial soaps havebeen used as well as bactericidal agents such as sulfur and resorcinol.Other topical compositions have separately contained benzoyl peroxide,hexachlorophene, erythromycin or neomycin sulfate. None of these priorpreparations has been completely effective.

As disclosed by Klein et al. (U.S. Pat. No. 4,497,794), it wasdiscovered that a mixture on the skin of a peroxide, especially benzoylperoxide and an antibiotic or antibacterial such as clindamycin,neomycin, sodium sulfacetamide, sulfur, tetracycline or erythromycin isparticularly beneficial as they can exert a statistically significantsynergistic effect. Peroxides inhibit the formation of free fatty acidsin the skin, primarily through inactivation of extracellular lipase (viaoxidation) necessary to cleave triglycerides into free fatty acids andglycerol. The antibiotic or antibacterial component reduces theconcentration of Corynebacterium acnes (i.e., P. acnes), a normalanaerobic bacteria which is the prime source of the lipase. Instead ofthe benzoyl peroxide, which is preferred, peroxides such as stabilizedhydrogen peroxide and peroxides of organic acids, such as a lauroylperoxide, may be used.

As disclosed by Klein et al., erythromycin and benzoyl peroxide may beapplied to the skin in combination in a preformulated aqueous-alcoholicgel. However, if a mixture is first made up and then applied to theskin, it is best that the mixture be made at the time of application orthat the mixture be used within twenty-four hours. The prompt use of apremix is necessary due to the chemical incompatibility of the twoactive agents. Because of this, it is advisable that the two agents beput in separate vials, bottles or other containers. For example, theKlein et al. patent discloses a kit containing, separately bottledliquid compositions comprising 5% benzoyl peroxide and a solution oferythromycin in ethanol or acetone.

However, separately packaging multiple dosages of the two activeingredients presents a number of disadvantages to the end-user. Forexample, a unit application dosage of each active must be removedsequentially from each container and absorbed onto an applicator, suchas a cotton swab, so that it can be coated onto the skin of the user.This provides opportunities for spillage or over- or under-dosing, whichcan lead to skin irritation and other side effects. Furthermore, such amultidose system necessarily adds to the costs of packaging, shippingand storage.

A dispensing and applicator system intended to overcome thesedifficulties is disclosed in U.S. Pat. No. 5,562,642. A dual-pad packageis disclosed therein that purportedly can contain, preserve and deliversingle unit doses of two or more chemically- or physically-incompatibleactive ingredients. For example, an antibiotic in combination with aliquid, semi-liquid (cream) or gelled aqueous or non-aqueous vehicle canbe absorbed by and retained by the first pad and a second ingredientwhich is physically- or chemically-incompatible with the antibiotic,such as a peroxide, can be absorbed and retained by the second pad,preferably in combination with the appropriate vehicle.

It would be desirable to provide a means for simultaneously dispensingtwo active acne treating compounds in aesthetically acceptable vehicleswhich allow prolonged shelf life for both active compounds and easymixing just prior to application to the skin.

SUMMARY

It has now been discovered that two separate compositions, onecontaining a first active ingredient which is effective in treating acneand one containing a second active ingredient that is incompatible withthe first active ingredient can be packaged within and dispensed from acommon dispenser. More particularly, a dual dispenser and has twochambers and a pump means for removing first and second compositionsfrom the chambers through one or more outlets. The first chambercontains a first composition that includes a first active ingredientthat is effective in treating acne; and the second chamber contains asecond composition containing a second active ingredient that isincompatible with the first active ingredient. Preferably, both thefirst and second active ingredients are effective against acne. Bypackaging the two active ingredients in this manner, long shelflife andconvenient dispensing and application are provided.

In one embodiment, the first active ingredient is an antibiotic and thesecond active ingredient is benzoyl peroxide. In an alternateembodiment, the first active ingredient is an antibiotic and the secondactive ingredient is a retinoid. In yet another embodiment, the firstactive ingredient is benzoyl peroxide and the second active ingredientis a retinoid.

In one particularly useful embodiment, a dual dispenser contains i) afirst composition that is substantially anhydrous and includes a polarsolvent, an antibiotic and a thickening agent selected from the groupconsisting of acrylic acid polymers and polyacrylamides; and ii) asecond composition containing benzoyl peroxide. In another particularlyuseful embodiment, a dual dispenser contains i) a first composition thatis substantially anhydrous and includes a polar solvent, an antibioticand a thickening agent selected from the group consisting of acrylicacid polymers and polyacrylamides; and ii) a second composition that issubstantially anhydrous, and includes a polar solvent, a retinoid, and athickening agent selected from the group consisting of acrylic acidpolymers and polyacrylamides. Preferably, in each embodiment the firstand second compositions have viscosities that differ by no greater than25%.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are described herein with reference to the drawingwherein:

FIG. 1 is an schematic view of a container suitable for dispensing thefirst and second compositions in accordance with this disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The dual dispensers described herein include a first chamber containinga first composition, a second chamber containing a second compositionand pump means for simultaneously dispensing the first and secondcompositions. The first and second compositions can be any cream,lotion, gel emulsion or suspension that is of an appropriate consistencyto be pumped out of the chambers by pump means. The first and secondcompositions can thus have a viscosity greater than about 1000centipoise (cps) when measured using a Brookfield viscometer (model LVT)at room temperature using spindle number 3 or 4 at 0.3 to 30 rpm. Itshould be understood that all viscosities referred to herein aremeasured in this manner. Preferably, the first and second compositionshave a viscosity greater than 5,000 cps. In particularly usefulembodiments, the compositions have a viscosity in the range of fromabout 1000 to about two million centipoise. Most preferably, the firstand second compositions have a viscosity in the range of about 10,000cps to about 1,000,000 cps. For purposes of presenting a compositionwith a good feel to the user, the first and second compositionsadvantageously have viscosities that differ by no greater than 25%.

The first composition contains a first active ingredient effective intreating acne. The first composition can be substantially anhydrous oraqueous. The first composition should be formulated to provide stabilityfor the first active ingredient. If the first active ingredient issusceptible to deterioration from contact with water, then the firstcomposition should be substantially anhydrous. By the term“substantially anhydrous” it is meant that, other than water ofhydration contained in the various components used to formulate thecomposition, no free water is added to the composition. Typically, thewater content of the composition will be less than 5% by weight.Preferably the water content of the composition is less than 3% and mostpreferably less than about 1% by weight of the composition. However,where the first active ingredient is not sensitive to water, thenaqueous formulations are acceptable for the first composition, includingsolutions, suspensions and water-in-oil emulsions.

One class of active ingredients known to be effective in treating acneis antibiotics. Preferably the antibiotic is one currently known to beuseful in treating acne, such as, for example, erythromycin,tetracyclin, clindamycin, their derivatives or pharmaceuticallyacceptable salts. The antibiotic is present in the first composition inan effective acne-treating amount, preferably an amount from about 0.001wt. % to about 5 wt. %, more preferably about 0.1 wt. % to about 1.0 wt.%.

In a particularly useful embodiment, the first composition issubstantially anhydrous and contains a polar solvent, a thickening agentand an antibiotic.

Polar solvents useful in this embodiment of the first compositioninclude polyols. A polyol is a compound with at least two hydroxylgroups per molecule, i.e., a compound having multiple hydroxyl groups aspart of its molecular structure. Among the useful polyols are polyhydricalcohols. Propylene glycol, dipropylene glycol, polyethylene glycol andglycerine are particularly preferred polar solvents for use in the firstcomposition.

The thickening agent used in this embodiment of the first composition isselected from the group consisting of acrylic acid polymers andpolyacrylamides. The thickening agent are used in an amount sufficientto obtain a composition of viscosity in the desired range.

Useful acrylic acid polymers include copolymers of (meth)acrylic acidand of monomers containing at least one fatty chain; these monomers arechosen from hydrophobic monomers with a fatty chain, amphiphilicmonomers containing a hydrophobic part with a fatty chain and ahydrophilic part, or alternatively their mixtures. Suitable materialsinclude, for example, copolymers of C₁₀₋₃₀ alkyl acrylates with one ormore monomers of acrylic acid, methacrylic acid, or one of their shortchain (i.e., C₁₋₄ alcohol) esters, wherein the crosslinking agent is anallyl ether of sucrose or pentaerythritol. These copolymers are commonlyreferred to as acrylates/C₁₀₋₃₀ alkyl acrylate crosspolymers and arecommercially available under the tradename CARBOPOL® from B.F. Goodrich,Cleveland, Ohio U.S.A. Other polymers useful in the preparation of thepresent compositions are polymers of polyacrylic acid crosslinked withfrom about 0.75% to about 2.0% of polyalkyl sucrose or polyalkylpentaerythritol often with molecular weights of 4 to 5 million or morethat are commercially available, for example, under the tradedesignation CARBOPOL® 934, 940 and 941 from B.F. Goodrich, Cleveland,Ohio U.S.A. Anionic amphiphilic polymers which comprise 95% to 60% byweight of acrylic recurring structural units, 4% to 40% by weight ofacrylate recurring structural units and 0.1 % to 6% by weight ofcrosslinking monomer, or (ii) which comprise 98% to 96% by weight ofacrylic recurring structural units, 1% to 4% by weight of acrylaterecurring structural units and 0.1 % to 0.6% by weight of crosslinkingmonomer are also useful as the thickening agent in the presentcompositions. Such polymers include, for example, thosehydrophobically-modified cross-linked polymers of acrylic acid havingamphipathic properties marketed by B.F. Goodrich under the trademarksCARBOPOL® 1342 and CARBOPOL® 1382. Also useful is ULTREZ® 10 (availablefrom B. F. Goodrich), an oil in water emulsion of a modified acryliccopolymer comprising of a major portion of a monoolefinicallyunsaturated carboxylic acid monomer or its anhydride having a length offrom about 3 to 6 carbon atoms and a minor portion of a C₈₋₃₀ chainacrylate or methacrylate ester monomer wherein the carboxylic acid orits anhydride is from about 80 to about 99% by weight and the C₈₋₃₀chain acrylate or methacrylate ester monomer is from about 1% to about20% by weight. The polymer is described in U.S. Pat. No. 5,004,598,hereby incorporated by reference in its entirety.

When used, these acrylic acid polymers are present in the firstcomposition at a level from about 0.05% to about 20%, preferably fromabout 0.5% to 10% and most preferably from about 1% to about 10%.

Where the first composition is an anhydrous antibiotic composition, thefirst composition can alternatively contain polyacrylamide polymers asthe thickening agent, especially nonionic polyacrylamide polymers.Useful non-ionic polymers are branched or unbranched polyacrylamides andsubstituted polyacrylamides. These polymers are non-ionic polymers whichcan be formed from a variety of monomers including acrylamide andmethacrylamide which are unsubstituted or substituted with one or twoalkyl groups (preferably C₁₋₅). Preferred acrylate amides andmethacrylate amides in which the amide nitrogen is unsubstituted, orsubstituted with one or two C₁₋₅ alkyl groups (preferably: methyl, ethylor propyl), for example, acrylamide, methacrylamide, N-methylacrylamide,N-methylmethacrylamide, N,N-dimethylmethacrylamide,N-isopropylacrylamide, N-isopropylmethacrylamide andN,N-dimethylacrylamide. These monomers are generally disclosed in U.S.Pat. No. 4,963,348 which is incorporated by reference herein in itsentirety. These copolymers may optionally be formed using conventionalneutral crosslinking agents such as dialkenyl compounds. The use of suchcrosslinking agents for cationic polymers is disclosed in U.S. Pat. Nos.4,628,078 and 4,599,379 both of which are incorporated by referenceherein. These non-ionic copolymers may have a molecular weight greaterthan about 1,000,000 preferably greater than about 1,500,000 and rangeup to about 30,000,000. Most preferred among these polyacrylamidepolymers is the nonionic polymer given the CTFA designationpolyacrylamide and isoparaffin and laureth-7, available under thetradename SEPIGEL® 305 from Seppic Corporation (Fairfield, N.J.). Otherpolyacrylamide polymers useful herein include multi-block copolymers ofacrylamides and substituted acrylamides with acrylic acids andsubstituted acrylic acids. Commercially available examples of thesemulti-block copolymers include Hypan SR150H, SS500V, SS500W, SSSA100H,from Lipo Chemicals, Inc., (Patterson, N.J.).

When used, these non-ionic polyacrylamides are present in the firstcomposition at a level from about 0.05% to about 20%, preferably fromabout 0.5% to 10% and most preferably from about 1% to about 10%.

Quite surprisingly, it has been found that contrary to productliterature relating to the commercially available acrylic acid polymersand polyacrylamides, when used to formulate the first composition as asubstantially anhydrous composition, the thickening agents need not bedispersed in an aqueous medium or neutralized to provide the desiredthickening.

Benzoyl peroxide is another active ingredient known to be an effectiveanti-acne treatment that can be incorporated into the first composition.Where benzoyl peroxide is the first active ingredient, the firstcomposition can be either substantially anhydrous or may contain waterand can be any benzoyl peroxide-containing cream, lotion, gel orsuspension. Examples of benzoyl peroxide compositions that are suitablefor use in accordance with this disclosure include, but are not limitedto the compositions disclosed in U.S. Pat. No. 5,632,996, the disclosureof which is incorporated herein by reference. In particularly usefulembodiments, the benzoyl peroxide composition is also substantiallyanhydrous. Among these embodiments are compositions containing a) apolar solvent, b) a thickening agent selected from the group consistingof acrylic acid polymers, polyacrylamides and combinations thereof (asdescribed above), c) benzoyl peroxide, d) alkyl benzoate and, optionallye) a synthetic cleanser. Suitable synthetic cleansers include, but arenot limited to sodium cocoyl isethionate, alpha olefin sulfonatesarcosynates and acyl glutamates.

The amount of benzoyl peroxide in the composition can be from about 0.1to about 20 percent by weight based on the total weight of thecomposition, preferably from about 1.0 to about 15 weight percent, mostpreferably from about 1.5 to about 10 weight percent. In thisembodiment, the benzoyl peroxide-containing composition can have aviscosity greater than about 1000 centipoise (cps) when measured using aBrookfield viscometer (model LVT) at room temperature using spindlenumber 3 or 4 at 0.3 to 30 rpm. Preferably, the benzoylperoxide-containing composition has a viscosity greater than 5,000 cps.In particularly useful embodiments, the benzoyl peroxide-containingcomposition has a viscosity in the range of from about 1000 to about twomillion centipoise. Most preferably, the benzoyl peroxide-containingcomposition has a viscosity in the range of about 10,000 cps to about1,000,000 cps.

In an alternative embodiment, the first composition contains a retinoid.Suitable retinoids, include, for example, retinol, retinoic acid,retinyl palmitate, retinyl propionate or retinyl acetate as well assynthetic retinoid mimics. The retinoid is preferably present in thesecond composition in an amount from about 0.001 wt. % to about 5 wt. %,more preferably about 0.1 wt. % to about 2.0 wt. %.

In a particularly useful embodiments, the retinoid-containingcompositions are also substantially anhydrous and contains a polarsolvent, a thickening agent and a retinoid. Suitable polar solvents andthickening agents for the second composition are the same as describedabove for the antibiotic and benzoyl peroxide compositions describedabove. In this alternative embodiment, the retinoid-containingcomposition can have a viscosity greater than about 1000 centipoise(cps) when measured using a Brookfield viscometer (model LVT) at roomtemperature using spindle number 3 or 4 at 0.3 to 30 rpm. Preferably,the retinoid-containing composition has a viscosity greater than 5,000cps. In particularly useful embodiments, the second, retinoid-containingcomposition has a viscosity in the range of from about 1000 to about twomillion centipoise. Most preferably, the second, retinoid-containingcomposition has a viscosity in the range of about 10,000 cps to about1,000,000 cps.

The second composition contains a second active ingredient that isincompatible with the first active ingredient. The second activeingredient may be effective in treating acne or may provide some otherbeneficial effect upon topical administration to a user's skin (such as,for example, alpha-hydroxy acids or anti-irritants The secondcomposition can be substantially anhydrous or aqueous. The secondcomposition is formulated to provide stability for the second activeingredient. If the second active ingredient is susceptible todeterioration from contact with water, then the second compositionshould be substantially anhydrous. However, where the second activeingredient is not sensitive to water, then aqueous formulations areacceptable for the second composition, including solutions, suspensionsand water-in-oil emulsions.

Combinations of first and second active ingredients for use in the firstand second compositions include but are mot limited to: a) anibiotic inthe first composition and benzoyl peroxide in the second composition; b)antibiotic in the first composition and a retinoid in the secondcomposition; and c) benzoyl peroxide in the first composition and aretinoid in the second composition.

The first and second compositions preferably have viscosities that aresimilar to provide a cosmetically elegant product when the first andsecond compositions are simultaneously dispensed. In particularly usefulembodiments the difference in viscosity between the first and secondcompositions is no more than about 25%.

In addition to the above-listed ingredients, one or both of the firstand second compositions may also contain a variety of non-essentialingredients such as, for example, co-solvents, preservatives,emollients, humectants, anti-inflammatory agents, antioxidants, insectrepellents or skin cooling compounds, etc. For example, either of thefirst or second composition may contain one or more co-solvents, such asethanol, acetone or propylene carbonate.

A preservative can also be used in either or both of the first or secondcompositions. Preservatives suitable for use in connection with thepresent compositions include parabens, sorbates, benzyl alcohol,diazolidinyl urea and isothiazolinones. Preservatives can be present inan amount from about 0.001 wt. % to about 15 wt. % of the totalcomposition.

One or both of the first or second compositions can also be formulatedto contain about 0.01 wt. % to about 30 wt. %, preferably about 1.0 wt.% to about 15 wt. % of the total composition, skin cooling compounds,such as menthol, methyl glycerol, asymmetrical carbonates,thiocarbonates and urethanes, substituted carboxamides, ureas orphosphine oxides as described in J. Cosmet. Chem., vol. 29, page 185(1978) and incorporated herein by reference, methyl lactate and menthoneglycerin acetal.

The first substantially and second compositions are stored in anddispensed from a multi-chamber dispenser. Dispensing systems thatinclude pump means suited for simultaneously dosing two separatelycontained incompatible compounds are well known. As such, the dispensingsystem schematically depicted in FIG. 1 (dispenser from Maplast,Tradate, Italy) is just one example out of a number of products whichrange from small, two-chambered single use pouches to tubes usingdifferent product compartments or tubes compartmentalized usingextrudable, viscous and relatively inert materials to separate theincompatible compounds.

The dispenser shown in FIG. 1 is able to simultaneously dose twocompounds separately contained in A and B by pressing dosing head C.Pressing dosing head C activates two small pumps which subsequentlydispense the two compounds in approximately equal volumes. Depending onthe design of the dosing head, the compounds can be dosed in twoseparate streams or in just one stream. If desired, a dispensing unitthat is able to deliver The first and second substantially anhydrouscompositions in a ratio, such as, for example, 1:2 can be used.Translated to the dispenser depicted in FIG. 1, this would mean that oneof the two pumps is able to dose at least twice the volume of the otherpump in just one stroke of dosing head C. Translated to a two-chamberedsingle use pouch, this would mean that the chamber containing the firstsubstantially anhydrous composition contains at least half as muchproduct volume as the other chamber. Translated to a two-compartmenttube, this would mean that under equal pressure the discharge orificefor the compartment containing the first substantially anhydrouscomposition allows the passage of at least twice as much product as thedischarge orifice of the other compartment. Translated to a tube whichis compartmentalized using extrudable material, this would mean thatfirst substantially anhydrous composition is present inside the tube inat least double the volume of the second substantially anhydrouscomposition.

Other suitable dispensers are disclosed in U.S. Pat. Nos. 5,356,040;5,823,391, and 4,826,048 the disclosures of which are incorporatedherein by this reference.

The following examples are presented to illustrate specific embodimentsof the present compositions and methods. These examples should not beinterpreted as limitations upon the scope of the invention.

EXAMPLES I-IV

The following formulations are exemplary of substantially anhydrousantibiotic compositions suitable for use as the first composition: I IIIII erythromycin 2 2 — propylene glycol 96 71.5 96.0  ULTREZ 10 2 1.52.0 polyethylene glycol — 25.0 — clindamycin — — 1.0 IV erythromycin 2.0propylene glycol 96.0 ULTREZ 10 1.0 SEPIGEL 305 1.0

EXAMPLES V-VI

The following exemplary benzoyl peroxide-containing formulations aresuitable for use as the second composition to be dispensedsimultaneously with any of the anhydrous formulations of Examples I-IV.V Petrotalium 15.50 Sodium Cocoyl Isethionate 5.00 Alfa olefin Sulfonate2.00 Titaniam Dioxide 0.30 Lucidol 75% (Benzoyl Peroxide) 15.80 C₁₂₋₁₅Alkyl Benzoate 7.00 Triethanolamine 0.60 Carbopol 1382 0.80 Glycerin58.0 VI - Gel Composition Water 56.4 Glycerine 5.0 SEPIGEL 305 2.0Sodium Hydroxide 1.60 Steareth S-20 2.0 Steareth S-2 2.0 Cetyl StearylAlcohol 3.0 Silicone Cupoydoyl 5.0 Lucidol 75% (Benzoyl Peroxide) 16.0C₁₂₋₁₅ Benzoate Ester 7.00 VII - Benzoyl Peroxide Gel propylene glycol88.5 ULTREZ 10 1.5 Benzoyl Peroxide 5.0 Fin Solv TN 5.0 VIII - BenzoylPeroxide Gel Cleanser glycerin 66.0 ULTREZ 10 2.0 Benzoyl Peroxide 5.0Fin Solv TN 5.0 Sodium Cocoyl Isethionate 20.0

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications ofpreferred embodiments. Those skilled in art will envision othermodifications within the scope and spirit of the claims appended hereto.

1. An apparatus comprising: a first chamber containing a firstcomposition, the first composition comprising an effective acne-treatingamount of an antibiotic; a second chamber containing a secondcomposition comprising a retinoid and water; pump means for moving thefirst and second compositions out of the first and second chambers; andone or more outlets for dispensing the first and second compositions. 2.An apparatus as in claim 1 wherein the retinoid is selected from thegroup consisting of retinol, retinoic acid, retinyl palmitate, retinylpropionate, retinyl acetate and synthetic retinoid mimetics.
 3. Anapparatus as in claim 1 wherein the antibiotic is selected from thegroup consisting of erythromycin, clindamycin, tetracycline, derivativesof erythromycin, clindamycin or tetracycline and pharmaceuticallyacceptable salts of erythromycin, clindamycin or tetracycline.
 4. Anapparatus comprising: a first chamber containing a first composition,the first composition comprising an effective acne-treating amount ofbenzoyl peroxide; a second chamber containing a second compositioncomprising a retinoid and water; pump means for moving the first andsecond compositions out of the first and second chambers; and one ormore outlets for dispensing the first and second compositions.
 5. Anapparatus as in claim 4 wherein the retinoid is selected from the groupconsisting of retinol, retinoic acid, retinyl palmitate, retinylpropionate, retinyl acetate and synthetic retinoid mimetics.
 6. A methodof treating acne comprising simultaneously pumping a first compositionand a second composition from first and second chambers, respectively,the first composition comprising an effective acne-treating amount of afirst active ingredient selected from the group consisting ofantibiotics and benzoyl peroxide, the second composition comprising aretinoid and water; and contacting the first composition and secondcomposition with the skin of a person afflicted with acne.
 7. A methodas in claim 6 wherein the retinoid is selected from the group consistingof retinol, retinoic acid, retinyl palmitate, retinyl propionate,retinyl acetate and synthetic retinoid mimetics.
 8. A method as in claim6 wherein the first active ingredient is benzoyl peroxide.
 9. A methodas in claim 8 wherein benzoyl peroxide comprises from about 0.1 to about25 weight percent of the second composition.
 10. A method as in claim 6wherein the first active ingredient is an antibiotic.
 11. A method as inclaim 10 wherein the antibiotic is selected from the group consisting oferythromycin, clindamycin, tetracycline, derivatives of erythromycin,clindamycin or tetracycline and pharmaceutically acceptable salts oferythromycin, clindamycin or tetracycline.
 12. A method as in claim 6wherein the first composition is substantially anhydrous.